BACKGROUND: Complete heart block is dreaded perioperatively in patients with chronic bifascicular or left bundle branch block (LBBB) and additional first-degree A-V block. Our aim was to investigate the necessity as well as the efficacy and safety of transcutaneous pacing in the perioperative setting. METHODS: Thirty-nine consecutive patients with asymptomatic chronic bifascicular block or LBBB and prolongation of the P-R interval scheduled to undergo surgery under anesthesia were prospectively enrolled in the study. Preoperatively, a transcutaneous pacemaker (PACE 500 D, Osypka Co.) was applied; its efficacy was checked with intra-arterial blood pressure measurement; the pain level was recorded. Additionally, 24-h Holter monitoring (CM2, CM5) was applied. Occurrences of a block progression or a bradycardia of <40 beats/min with hemodynamic impairment were the defined end points. RESULTS: Thirty-seven of the 39 patients (95%) could be successfully stimulated with a median current strength of 70 mA; whereby 33 of the 39 patients felt moderate to severe pain. There was no perioperative block progression. Three cases of brady-cardia of <40 beats/min with a critical drop in blood pressure occurred; but these patients were successfully treated with drug therapy without pacemaker stimulation. CONCLUSION: The perioperative application and testing of the pacemaker was safe and could be performed in nearly all patients successfully. However, we do not consider a routine prophylactic transcutaneous placement in patients with chronic bifascicular or LBBB and additional first-degree A-V block justified. Nevertheless, appropriate drugs and temporary pacemaker equipment should be easily accessible.